Bosch Power Tools 3727DEVS, 3725DEVS manual Tool Tips

BM 2609932842 03-12_BM 2609932842 03-12.qxp 3/12/12 9:21 AM Page 11

"LOCK-ON" BUTTON

The "Lock-ON" button, located near the trigger allows for continuous operation at maximum OPM without holding the trigger (Fig. 1).

TO LOCK TRIGGER "ON": squeeze trigger, depress button and release trigger.

TO UNLOCK THE TRIGGER: squeeze trigger and release it without depressing the "Lock- ON" button.

If the “Lock-ON” button is

!WARNING continuously being depressed, the trigger can not be released.

VARIABLE SPEED WITH DIAL SETTING

Your sander is also equipped with a variable speed dial. The sander's orbital pad speed can be preset from zero to maximum nameplate OPM by rotating the dial in the housing. The dial may be set on or between any of six positions (1=low through 6=high). The "Lock- ON" button may also be used with any setting of the dial.

The following table may be used as a general guide for abrasive and backing pad selection, but the best results will be obtained by sanding a test sample of the workpiece first.

Switch Backing Grit

Material setting pad size

rough/finishrough/finish

woods:
softwoods	4 / 6	extra soft	60	/ 240
hardwoods	4 / 6	soft	60	/ 180
veneers	4	soft	240	/ 320
metals:
steel	4	soft	60	/ 240
stainless	4	soft	120	/ 240
aluminum	4/ 6	soft	80	/ 240
rust spots	6	extra soft	60	/ 120
paintwork:
sanding	2 / 3	soft	180	/ 400
scratches	4 / 6	hard	120	/ 240
stripping	4	soft	40/60 /80

Tool Tips

SELECTING SANDING DISCS

Open-coat aluminum oxide sanding discs are recommended for most wood or metal sanding applications, as this synthetic material cuts quickly and wears well. Some applications, such as plastics, glass, or stone require silicon carbide discs, which have a very sharp cutting edge. For best results, use Bosch sanding and polishing accessories, which are of superior quality and are carefully selected to produce professional quality results with your sander.

START OF SANDING

With the workpiece firmly secured, place the pad on the work surface, then switch the tool on. DO NOT apply excessive pressure as this will slow the pad action, and DO NOT start the tool and bring it up to speed before applying to the work; swirl marks will result in either case.

SANDING ACTION

This sander has optimized random sanding action. The pad orbits and rotates freely, duplicating natural hand sanding action for aggressive stock removal and smooth, well- blended surface finish. The orbit offset for this tool is 2 mm (5/64")

In general, higher speeds will give the best results. If faster removal is desired, DO NOT

APPLY PRESSURE ON THE TOOL; use a coarser grade of abrasive. Move the sander in long sweeping strokes, parallel to the grain using some lateral motion to overlap the strokes by as much as 75%. The random orbit action allows cross-grain sanding, but be careful not to tilt the sander near edges, or undesirable rounding may result.

SANDING SEQUENCE

If the surface is rough, begin with coarser grits and then complete the surfacing with medium and fine abrasives. Because the random orbit action is so effective, it is often possible to begin sanding with a medium grit disc and go directly to fine finishing. To avoid uneven results, do not skip more than one grit size when going from coarser to finer, and do not sand in one area for too long.

REMOVAL OF SANDER

To help prevent swirl marks when the job is completed, gently lift the tool from the work surface, then switch the tool off.

POLISHING

For most polishing, the extra-soft backing pad will give the best results. The random orbit sander may be fitted with an optional foam buffing pad or polishing bonnet to polish or remove scratches from painted or finished

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